It is well known that synchronizers may be used in multiple speed ratio transmissions to assist shifting of all or some of the transmission gear ratios. It is also known that the shift effort and/or time to perform a shift may be reduced by use of synchronizers of the self-energizing or boost type. Since required operator shift effort generally increases with vehicle size, synchronizers of the self-energizing type are especially useful in transmissions for heavy duty trucks and/or in transmissions where reduced shift time and/or reduced shift effort are preferred. Prior art examples of synchronizers that may be relevant to the synchronizer herein may be seen by reference to U.S. Pat. Nos. 5,078,245; 5,092,439; Japanese Patent Publication (Kokoku) 45-27483; and German Patent Publication 1,098,824 which are incorporated herein by reference.